This invention relates to a waterwall and, more particularly, to a waterwall that has been provided with a surface that is resistant to erosion caused by particulate material.
Most erosion in industrial processes occurs where large volumes of abrasive particles such as coal, catalyst, sand, shale, limestone, etc. change direction of flow via elbows, tees, separators, swirl vanes and the like. The erosion occurs as a result of low angle impingement by large volumes of the abrasive particles which move at varying velocities.
Several systems have been devised to resist this type of erosion. For example, monolithic, cement or phosphate bonded castable (and plastic) refractories held by steel anchors on about two or four-inch staggered centers, or on a hexagonal steel grid have been utilized to resist the above erosion. Also, a considerable thickness, up to several inches of the above mentioned refractories, have been installed on V-bar or S-bar anchors, and if the erosion is exceptionally severe a prefired refractory is used which is usually bolted to the steel structure.
However, the use of these refractories increase the thermal conductivity which, in many systems, seriously affects heat absorption rates to the tubular surfaces in fluidized bed boilers, for example.
It has been discovered that a steel support system is more erosion resistant than most of the monolithic cement-bonded, castable refractories discussed above that are traditionally used in studded anchor wall systems. However, if the tube enclosure walls were simply designed with a greater thickness of steel, the weight and cost increase could be prohibitive.